1. Field of the Invention
The present invention relates generally to pneumatic tools, and, particularly, relates to portable pneumatic tools, and, in greater particularly, relates to devices for controlling the flow of gas thereto.
2. Description of the Prior Art
With the advancement of technology in the construction industry, the use of powered portable devices has become more common. Typically, such devices were powered by an electric generator which converted the AC to DC power as needed or ran a compressor. The powered devices were connected by long electrical cords or air hoses to these devices. The disadvantages are clearly evident such as safety from tripping over cords and hoses, limited range, limited number of operating devices, and the need to transport heavy generators and compressors to construction sites. The next generation of portable powered devices use compact batteries and bottled compressed gas. In regards to portable powered devices using compressed gas, stepping down the gas pressure requires the use of complex pressure regulators.
In particular, pressure regulators are commonly used in the construction trades to regulate the pressure received by pneumatic tools from compressors or other pressure sources. These tools have an optimum range of operation for the pressurized fluid stream which provides them energy to operate. However, most compressors and other conventionally used pressurized fluid stream sources operate at fluid pressures well above the optimum range required by the tool connected to them.
Common power tools such as pneumatic air hammers which drive nails into wood, pneumatic staplers, and pneumatic saws used in construction, and in other applications such as dental offices, require a constant regulated fluid stream to operate effectively. Currently such a regulated pressurized fluid stream is maintained by a fluid pressure regulator located between the conventional pressurized fluid source and the connected tool.
Once such regulator is disclosed by U.S. Pat. No. 5,860,447 that is a single stage pressure regulator with a bleed piston cooperatively engaged thereto. In the normal state of operations, the output pressure pushes the regulator piston against the bleed piston. When the source of pressure is removed from the regulator, the bleed piston is forced to open the seal and this allows the compressed gas in the tool to flow through the regulator piston, and out through bleed vents and thus “de-energizing” the pressure operated tool to prevent accidental operation.
Another regulator of pressurized gas is disclosed by U.S. Pat. No. 7,325,397 that is particularly directed at providing power to nail guns. Because of the high pressure in the carbon dioxide container, a two stage regulator is used. The first regulator reduces substantially the pressure to just above a desired amount. A fine pressure adjustment unit is connected down line from the first regulator and is used to bring the operating pressure into the range to be used by the pneumatic tool such as a nail gun. Neither of the patents are concerned with the occurrence of pressure spikes, high or low, in the input stream.
Accordingly, there is an established need for a compensating pressure regulator having means for eliminating transient spikes.